1. Field of the Invention
The present invention relates to an apparatus and method of recovering lithium cobalt oxide from lithium batteries that have already been depleted of their energy. More particularly, the recovering technology concerns the recycling of lithium cobalt oxide from spent lithium batteries. At the end of the life of the batteries, the batteries are dismantled to separate the electrode materials from the waste and to recover selectively only the cathode active materials under a hydrothermal condition.
2. Description of the Prior Art
Generally, a lithium battery having properties of highly dense energy and a low weight is the major power source for most small portable electrical equipment. Recently, usage of lithium ion secondary batteries has rapidly increased.
A lithium ion secondary battery comprises an anode, a cathode, an organic electrolyte and an organic separator. Lithium cobalt oxide has properties of excellent reversibility, low discharging rate, high capacity, high energy density, and easy synthesis. Lithium cobalt oxide is presently commercialized as the active material in lithium ion secondary batteries.
A lithium ion secondary battery comprises a cathode, which is an electric collecting aluminum plate coated with a mixture of carbon group and organic compounds, using lithium cobalt oxide as the active material; an anode, which is an electric collecting copper plate coated with a mixture of carbon group of graphite and organic compounds, as a cathode active material; an organic electrolyte, dissolved in an organic separator and lithium salt in an organic solvent formed as a unit cell; and a combination of more than one unit cell packaged in plastic with a charging protection IC chip.
A lithium ion secondary battery comprised of such compositions as mentioned above has the capability of charging and discharging with a relatively longer life span. However, it has a limited life span of about 500 cycles. Therefore, the number of disposed batteries increases as the consumption of batteries increases. However, the spent lithium ion batteries contain relatively valuable organic metals, such as lithium and cobalt, with a simple crystal structure. Thus, the waste is still considered economically valuable.
From the recycler's viewpoint, spent lithium batteries have the above-mentioned advantages. However, the organic electrolyte, organic separator, and plastic materials used for the external battery are hard to dispose of due to the toxic substances they contain which contaminate the environment. Therefore, those materials must be recycled to recover valuable resources and also to protect the environment.
However, the technology for recycling spent lithium batteries is in the initial stage of development in Korea. In Japan, the technologies for recycling lithium primary batteries, lithium ion secondary batteries, and scraps produced during the manufacturing process are in the practical stages.
Also, the technology for recycling spent lithium ion secondary batteries still needs improvement. Specifically, the technology needs a means of excluding foreign materials, a moderate process for preventing excessive crashing, and a technique for concentrating valuable metals by selectively separating anodizing materials.